Socket wrenches have been known for many years and a particular form of socket wrench is that commonly found as an accessory to automobiles to loosen and tighten wheel nuts when the operator is changing a tire. Wheel nuts require a significant force both to loosen and properly tighten and to provide for the necessary torque, the wrench usually has a long handle, often so long that it is difficult to rotate the wrench 360 since the end of the handle invariably hits the ground. Frequently when a nut is loosened by the wrench, the user removes the wrench only to find that the force needed to further turn the nut is too great for the fingers. The wrench must then be used to further turn the nut until it is sufficiently loose so that it can be removed using the fingers. This problem is of course, compounded with those wheel nuts located at the bottom of the wheel where the clearance with ground is less.
Although ratchet type of socket wrenches are known, they are relatively expensive and in most cases rely on some friction between the nut and bolt or lug in order for the ratchet mechanism to work. Often that friction may be greater than what fingers are capable of overcoming.
Accordingly, there developed a need for a wrench which has the capability of handling the requirement of significant leverage operation to loosen or tighten nuts or the like but which also has a free spin or wheeling capability whereby the loosened nut may be positively but relatively easily rotated by means other than the fingers directly on the nut.
Devices which are directed towards the above object are shown in U.S. Pat. No. 151,315, May 26, 1874 to Rowe; French patent 662,028, Mar. 1929 to Mougeotte; U.S. Pat. No. 2,621,688, Dec. 16, 1952 to Wales and British patent publication 2,057,943 A, published Apr. 1981 to Giacchero et al.
The Canadian patent to Rowe relates to carriage wrenches wherein there is an elongate lever having an end surrounding and adapted for detachable connection with the stem of nut socket. A knob on the end of the stem can be used to freewheel the socket when detached from the stem or to maintain it in cooperative connection with the lever end.
The French patent to Mougeotte relates to a socket wrench for automobiles and also has an elongate lever connected to a hub having ratchet means which selectively cooperates with ratchet means on a stem portion of a socket. The stem portion of the socket is connected to a small crank handle by a shaft through the hub and is selectively rotatably and axially slidable relative to the hub.
The U.S. patent to Wales relates to a lever arm screwdriver and wrench wherein a freewheeling knob is associated with a shaft connected to a specifically configured driver tool. A stem connected to the lever arm and through which the shaft extends, has a recess of complementary configuration to that of the driver tool. A detent in the lever stem of the spring biased ball type cooperates with a groove on the shaft.
The British patent publication to Giacchero et al discloses a spanner for nuts and bolts having an operating lever with a handle at one end and a transverse sleeve at the other in which there is rotatably and axially slidably mounted a shaft. The opposite ends of the shaft respectively carry a removable socket usable for turning nuts and a freewheeling operating handle. The sleeve and shaft carry coupling means for selectively coupling the shaft to the sleeve. There is provided a spring-biased ball detent mechanism cooperating with grooves in the shaft and the sheath of plastic surrounding the sleeve provides protection to the sleeve and means through which markings or words may be stamped or written.
Other than the device of Rowe which does not provide any detent mechanism, the detent mechanisms of Wales and Giacchero et al require special making of grooves on the shaft and of holes in the hub for the spring and ball system. Additionally the spring and ball add to the cost of production of the device and may, as in the case of the Giacchero et al device, require a plug to maintain them in operative position. The spring-biased ratchet system of the Mougeotte device requires special machining of the ratchet teeth and assembly with a spring.
Accordingly there appears a need to provide a wrench having a high leverage capability and a low leverage, freewheeling capability which is simple to manufacture without extensive machining, is easy to assembly and yet provides a detent mechanism which is positive in actuation.